Atrial fibrillation (AF for short) is the most common persistent clinical arrhythmia. The prevalence of atrial fibrillation among adults in China is about 0.7%; and the incidence increases gradually with age. During an episode of atrial fibrillation, the atrial excitation frequency can reach 350-600 beats per minute and is absolutely irregular; the atria lose their effective contraction function; the frequency of downward transmission to the ventricles through the atrioventricular node is about 100-160 beats, and the rhythm is absolutely irregular. The heart’s ability to pump blood is reduced by about 25%. The normal heart anatomy and physiological functions The human heart has four chambers: the left atrium, the left ventricle, the right atrium, and the right ventricle. The heart is a hollow, muscular organ filled with blood, and the blood between the left and right chambers does not communicate with each other. It acts like a “pump”, sending blood to all organs of the body through rhythmic systole and diastole to deliver the oxygen and nutrients needed to maintain normal function of the body’s organs. The normal cardiac conduction system The contraction and diastole of the heart are triggered by electrical excitation. In the heart, there are not only places to generate “electrical excitation” but also channels to conduct “electrical excitation”, which is usually called the cardiac conduction system. In this system, the sinus node, located in the right atrium, is responsible for generating regular electrical excitation, which is transmitted rapidly and sequentially throughout the heart through the cardiac conduction system in the atria, atrioventricular node and ventricles, and triggers the heart’s rhythmic contraction and diastole to complete the pumping function. The normal heart rate is 60-100 beats per minute in a regular rhythm, which is called sinus rhythm. What is an arrhythmia An arrhythmia is an abnormality in the frequency or rhythm of the heartbeat. An abnormality in the function of any part of the heart’s conduction system can lead to an arrhythmia. During an arrhythmia attack, patients often experience palpitations, chest tightness, shortness of breath, and in severe cases, vertigo, syncope, or even sudden death. According to the frequency of heartbeat during an attack, there are two major types of arrhythmias: fast and slow. There are two main types of mechanisms for the occurrence of tachyarrhythmias, one is a focal mechanism of abnormal origin and the other is a foldback mechanism caused by the presence of abnormal conduction bundles. Diagnosis of arrhythmias A preliminary diagnosis can be made by the ECG or 24-hour ambulatory ECG monitoring (Holter) recorded during an arrhythmia attack, supplemented by some symptoms accompanying the attack. However, if the location and mechanism of the arrhythmia need to be clarified, electrophysiological examination is required.